On NBER it appears that PAYIFABS is in all months, not just ASEC. Why is it only for ASEC months here?

On NBER it appears that PAYIFABS is in all months, not just ASEC. Why is it only for ASEC months here?

While IPUMS-CPS is constantly expanding the variables that we offer, the PAYIFABS variable has not yet been included for basic monthly samples. For now, you can follow the directions for merging the IPUMS-CPS basic monthly samples with the NBER basic monthly samples, as described in this previous answer.

Hope this helps.